1. Field of the Invention
This invention relates to a transmission apparatus having a split-coil type coaxial coupler for transmitting electric power, digital signals, digitized data signals or analog signals without making contact, using electromagnetic waves or electromagnetic induction. This invention is effectively used in, for example, NC machine tools, robot apparatus, carrying apparatus, driving handles of vehicles and the like, various other kinds of automatic machines and the like, when a moving-side module and a fixed-side module are mounted on a rotating body and a body of an apparatus, respectively. Electric power and command signals required at the rotating side and data signals (for example, a shape, position, temperature, color and the like) are transmitted from the rotating side to the fixed side.
2. Description of the Prior Art
As a transmission apparatus of this kind, there are known FM telemeters, various kinds of transmission apparatuses which utilize electromagnetic waves or light as a medium, wireless modems and the like. Recently, in particular, handling has become remarkably easier than in conventional cases in that, for example, by using a coaxial cylindrical coupler, a power supply needed at the rotating side is transmitted from the fixed side without making contact, and so the moving side needs no power supply.
Such a coaxial cylindrical coupler comprises inner and outer solenoid coils. There are many inconveniences, however, For example, when the solenoid coils are mounted on a rotating shaft, a hole having a diameter large enough for fitting the rotating shaft is provided at the inner side of a rotating-side module having the solenoid coil, and the module is mounted by threading the rotating shaft through the hole, or spools are arranged so as to be able to be divided into two portions, and coils are manually wound after installing the spools.
Apart from when a machine is newly manufactured, when the above-described module is to be mounted on an existing machine, or in the case of trouble after mounting the module, it is necessary to disassemble the machine to take out the rotating shaft, or wind or untie the coil. These operations are extremely troublesome.